In the prior art, the use of glass fiber reinforced concrete (GFRC) as a building material is well known. Typically this material is made up of a composite that is reinforced with alkali-resistant glass fibers. The matrix material is made up of cement, sand, an acrylic based co-polymer, e.g., a styrene-butadiene polymer, known in the trade as Forton®, water, and other components such as plasticizers, silica fumes, and metakaolin clay. The typical amount of the acrylic-based co-polymer is around 14% by weight, which equates to about 7% wt of solids since the polymer is roughly 50% water. The durability of the composite is greatly improved through the use of the acrylic based co-polymer. This polymer penetrates into the inter-filamentary gaps of the glass fiber bundles (due to capillary action) and disperses throughout the entire matrix between the cement and sand particles. When the mortar dries sufficiently, through evaporation and the start of hydration, the polymer particles will adhere to each other, resulting in a cohesive polymer film, which is uniformly spread throughout the reinforced matrix, thus coating the sand, cement, and glass fibers. This polymer films acts as a barrier to further evaporation, the barrier effectively sealing the composite to retain the water of hydration, and a need for a wet cure is eliminated.
Metakaolin clay is used in GFRC to enhance the durability, strength, and workability. Plasticizers are used to wet all of the dry cement and sand particles, thereby reducing chemically-uncombined water and the problems that the presence of this water may have on the finished product.
While GFRC provides a totally acceptable product in many applications, it does suffer from the problem of low compressive and flexural strength, and this problem is magnified when the GFRC is used in structures needing these properties. Accordingly, a need exists for matrix compositions reinforced by glass fiber that exhibit improved properties, and particularly flexural strength. The present invention satisfies this need by providing a cement-containing and sand free composition employing effective amounts of cement, a superplasticizer, a metakaolin clay, an acrylic-based co-polymer, and water, which is especially adapted for use in manufacturing poles.